Australian Institute of Criminology

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Alleged offenders tell truth about drug use

Media Release

31 July 2003

A paper examining the extent to which participants in the Drug Use Monitoring in Australia (DUMA) program under-report their recent drug use has been released by the Australian Institute of Criminology today. DUMA collects confidential and voluntary data on drug use from people detained by police. Participants are asked to answer questions about their use of drugs, as well as supply a urine sample. This sample is tested for the presence of illicit drugs and compared with the self-reported answers in the questionnaire.

"It is commonly believed that people will understate their drug use. However this research shows that detainees are reasonably accurate in reporting their recent drug use", said Dr Adam Graycar, AIC Director. "In fact, among all adult detainees who provided a useable urine sample, there is a high total concordance rate between self-reported illicit drug use during the past two to three days and the results of the urinalysis - 92 per cent for heroin, 86 per cent for methamphetamine and 98 per cent for cocaine", he said.

The study also found:

  • Detainees with the most to lose were more likely to under-report their drug use. Older detainees living in their own home and employed full time are more likely to under-report their drug use than younger detainees who are not employed full time and living in a home not their own.
  • More serious offenders and/or offenders with a history of criminal behaviour or those in treatment were more likely to report their drug use accurately. Others who lead a more socially accepted lifestyle are more likely to under-report their drug use. Given this, the context in which studies of general populations and high-risk groups are conducted need consideration, as unfavourable circumstances may lead to a high level of under-reporting.